The goal of this work is to evaluate MR exams for prognostic information about acute ischemic stroke. The MR components are: DWI, perfusion imaging which provides information about tissue perfusion, and phase contract (PC) MR which supplies data about blood flow. To date, we have studied over 140 patients and currently image an average of 5 patients per week. Methods and Results The effectiveness of the new method is demonstrate~ in Figure 22.)The DWI images were efficient in detecting small strokes., Figure 23 shoWs the complete set of images from the diffusion protocol performed on a 67-year Qld mjile with a4-day old infarct. The phase corrected DWI images area free of motion artifacts. Heterogencity in ADC values is noticeable within the infarct, as well as destruction of diffusion anisotropy effects in the same area. In this and other slices, areas of T2-weighted hyperintensity correlated well with the corresponding hyperintense diffusion-weighted regions, except in areas close to the ventricles where CSF and infarct appear isointense on T2 scans but are clearly differentiated on the diffusion images. ADC variations from within the lesion ranged from 35% to 90% of normal, suggesting large differences in either infarct age or tissue type. The '1raw" diffusion weighted images were found to be most useful in detecting stroke lesions, since ischemic tissue generally shows up bright while all other tissues are dark or isointense. Discussion Although an improvement over other non-single shot diffusion techniques, the navigated diffusion sequence still benefits significantly from patient cooperation and a moderate amount head immobilization. Nonetheless, the ability to acquire good quality diffusion-weighted images on standard MR scanners could provide the long-anticipated clinical promise of this unique method for detecting and characterizing stroke.